The error message displayed in my case was looking for a version of my icon with an x in the name. So my icon is named "icon_V_PlateCarrier1_PMC_rgr" but it seems to be looking for "icon_V_PlateCarrier1_PMC_x_rgr"
Refer to bi thread which includes more information including my config file and pictures of errors
http://forums.bistudio.com/showthread.php?161494-Issues-with-config-for-ammo-crate-with-custom-gear